Process for the removal of straight chain hydrocarbons from petroleum fractions

ABSTRACT

A PROCESSS FOR THE PRODUCTION OF AN EDIBLE YEAST PRODUCT WITH A CONCURRENT DEWAXING OF A PETROLEUM FRACTION CONTAINING INITIALLY FROM 3 TO 45% BY WEIGHT OF N-PARAFFIN, SAID FRACTION FURTHER CONTAINING BRANCHED-CHAIN PARAFFINS, NAPHTHENES AND AROMATICS. SAID PROCESS PRODUCES A DEWAXED GAS-OIL PRODUCT THUS RENDERED MORE SUITABLE FOR INDUSTRIAL USE THROUGH A REDUCED PROPORTION OF N-PARAFFIN AND AN EDIBLE YEAST PRODUCT WHICH IS CULTIVATED AT THE EXPENSE OF THE N-PARAFFIN INITIALLY PRESENT.

v 1'' 3,560,341 Umted States Patent 0 ,C PM... Feb. 2, 1971 3,560,341PROCESS FOR THE REMOVAL OF STRAIGHT CHAIN HYDROCARBONS FROM PETROLEUMFRACTIONS Alfred Champagnat, Paris, and Jean Antoine Filosa, Lavera,France, assignors to The British Petroleum Company Limited, London,England, a British jointstock corporation No Drawing. Continuation ofapplication Ser. No.

330,520, Dec. 16, 1963, which is a continuation-inpart of applicationsSer. No. 131,470, Aug. 15, 1961, now Patent No. 3,193,390, and Ser. No.228,728, Oct. 5, 1962. This application Aug. 15, 1968, Ser. No. 755,019The portion of the term of the patent subsequent to June 21, 1983, hasbeen disclaimed Int. Cl. C12c 11/00; C12d 13/06; A23j 1/18 US. Cl. 195-310 Claims ABSTRACT OF THE DISCLOSURE A process for the production of anedible yeast product with a concurrent dewaxing of a petroleum fractioncontaining initially from 3 to 45% by weight of n-parafiin, saidfraction further containing branched-chain parafiins, naphthenes andaromatics. Said process produces a dewaxed gas-oil product thus renderedmore suitable for industrial use through a reduced proportion ofn-paraffin and an edible yeast product which is cultivated at theexpense of the n-paraffin initially present.

This application is a continuation application of application Ser. No.330,520, filed Dec. 16, 1963 (now abandoned), which is in turn acontination-in-part of application Ser. No. 131,470, filed Aug. 15, 1961(which has issued into US. Pat. 3,193,390), and application Ser. No.228, 728, filed Oct. 5, 1962, now abandoned.

Thi invention relates to a process for the removal of straight chainhydrocarbons, wholly or in part, from petroleum fractions in which theyare contained and, more particularly, to a combined process foreffecting said removal of hydrocarbons from petroleum fractions with theproduction of edible yeasts.

It is well known that certain petroleum fractions, particularly gasoils, contain straight chain hydrocarbons, mainly paraflins which arewaxes and which have an adverse eifect upon the pour point of thefraction; that is to say, when these hydrocarbons are removed, wholly orin part, the pour point of the fraction is lowered. Usually the wax isremoved by precipitation by means of solvents, the wax originallypresent in the fraction being recovered as such, that is, withoutconversion to more valuable products.

The petroleum fractions boiling below the gas oils, for example, heavynaphthas and kerosines also contain straight chain hydrocarbons whichare potentially valuable for conversion to other products but hitherto,in general, utilisation of these hydrocarbons has been rendereddifficult by the necessity of recovering these hydrocarbons from thepetroleum fractions, in which they are contained, before they can beconverted to other products.

It is also well known that food yeasts, suitable for consumption bycattle, or in some cases by human beings, are prepared using as startingmaterials carbohydrates, for example molasses, wood hydrolysis sugarsand lyes obtained in the course of paper manufacture.

It is an object of the present invention to provide a process for theremoval wholly or in part of straight chain hydrocarbons from petroleumfractions with the recovery of a valuable product based on the originalstraight chain hydrocarbon content of the petroleum fraction. It is afurther object to provide a process for the dewaxing of a petroleum gasoil fraction with the production of edible yeast. Other objects willappear hereinafter.

According to the present invention there is provided a process whichcomprises cultivating a strain of yeast which is adapted to grow onstraight chain paraffiuic hydrocarbons, in the presence of a petroleumfraction consisting in part of straight chain hydrocarbons and having amean molecular weight corresponding to at least 10 carbon atoms permolecule, and in the presence of an aqueous nutrient medium; and in thepresence of a gas containing free oxygen and separating from themixture, on the one hand, yeast and, on the other hand, a petroleumfraction having a reduced proportion of straight chain hydrocarbon orwhich is free of said straight chain hydrocarbons.

The process of the invention is of particular value for the treatment ofpetroleum gas oil fractions which contain straight chain hydrocarbons inthe form of waxes, since by the process of the invention a gas oil ofimproved pour point is obtained while the waxes are converted to avaluable product.

Usually the straight chain hydrocarbon will be present in the feedstocksaccording to the invention as paraffins; however, olefins may also bepresent.

It is an important feature of this invention that when cultivatingyeasts in the presence of the feedstocks hereinbefore described underconditions favouring the growth of the yeasts as the expense of thestraight chain hydrocarbons, the other hydrocarbons, for exampleisoparaffins, naphthenes and aromatics, are not metabolised or, at most,the proportion which is metabolised is very small. Furthermore, unlikeconventional chemical process governed by the law of mass action, therate of removal of straight chain hydrocarbons is not substantiallyreduced as the proportion of these hydrocarbons in the overall mixtureof hydrocarbons decreases (except, of course, in the very final stagesof removal). Thus, when desired, the percentage conversion of straightchain hydrocarbons which is achieved can be maintained at a valueapproaching 100% without necessitating a very disproportionateexpenditure of content time to achieve small improvements. Furthermore,in a continuous process, this high percentage conversion can be achievedwithout resorting to the use of a long reaction path.

By the application of this process under conditions which limit themetabolisation of the straight chain hydrocarbons it is possible tooperate with the removal of only a desired proportion of thesehydrocarbons.

Suitable feedstocks to the process of the invention include kerosine,gas oils and lubricating oils; these feedstocks may be unrefined or mayhave undergone some refinery treatment, but must contain a proportion ofstraight chain hydrocarbons in order to fulfil the purpose of thisinvention. Suitably the petroleum fraction will contain 3-45 by weightof straight chain hydrocarbons.

Preferably when a yeast is employed this is of the familyCryptococcaceae and particularly of the subfamily Cryptococcoideae;however, if desired there may be used, for example, ascosporogeneousyeasts of the subfamily Saccharomycoideae. Preferred genera of theCryptococcoideae subfamily are Torulopsis (also known at Torula) andCandida. Preferred strains of yeast are as follows. In particular it ispreferred to use the specific stock of indicated reference number; thesereference numbers refer to CBS stock held by the Central Bureau vorSchimmel culture, Baarn, Holland and to INRA stock held by the InstitutNational de la Recherche Agronomique, Paris, France.

Candida lipolylica Candida pnlcherrimaCBS 6l0 Candida util is Candidautilis, Variati major-CBS 841 Candida trpicalisCBS 2317 T orzdopsisc0llicul0sa-CBS 133 Hansennla an0ma[aCBS 110 Oidium lactis Neurosporasitophild Mycoderma cancoillote-INRA; STV 1 1 Of the above Candidalipolytica is particularly preferred.

A suitable nutrient medium for yeasts has the composition:

Grams Diammonium phosphate 2 Potassium chloride 1.15 Magnesium sulphate,7H O 0.65 Zinc sulphate 0.17 Manganese sulphate, lH O 0.045 Ferroussulphate, 7H O 0.068 Tap water, 200. Yeast extract 0.025

Distilled water (to make up to 1000 ml.)

When starting with a fresh stock of the yeast it will usually benecessary to adapt the yeast to assimilate carbon from hydrocarbons andto use an inoculum of the adapted yeast for the process of growthaccording to the invention. However these yeasts, when cultivated on anaqueous mineral medium containing the appro priate nutrient elements,grow with difficulty because the petroleum fractions do not contain thegrowth factors which exist in molasses and Wood hydrolysis sugars, forexample.

The growth of the yeasts used is favoured by the addition to the culturemedium of a very small proportion of extract of yeast (an industrialproduct rich in vitamins of group B obtained by the hydrolysis of ayeast) or more generally of vitamins of group B and/ or biotin. Thisquantity is preferably of the order of 25 parts per million withreference to the aqueous fermentation medium. It can be higher or loweraccording to the conditions chosen for the growth.

The growth of the yeast takes place at the expense of the petroleumfraction with the intermediate production of bodies having an acidfunction, principally fatty acids, in such manner that the pH of theaqueous mineral medium progressively diminishes. If one does not correctit the growth is fairly rapidly arrested and the concentration of theyeast in the medium, or cellular density, no longer increases so thatthere is reached a so-called stationary phase.

Preferably therefore the aqueous nutrient medium is maintained at adesired pH by the step-wise or continuous addition of an aqueous mediumof high pH value. Usually, and in particular when using Candidalipolytica, the pH of the nutrient medium will be maintained in therange 3-6 and preferably in the range 45. Suitable alkaline materialsfor addition to the growth mixture include sodium hydroxide, potassiumhydroxide, disodium hydrogen phosphate and ammonia, either free or inaqueous solution.

The optimum temperature of the growth mixture Will vary according to thetype of yeast employed and will usually lie in the range 25-35 C. Whenusing Candida Zipolytica the preferred temperature range is 2832 C.

The take-up of oxygen is essential for the growth of the yeast. Theoxygen will usually be provided as air. In order to maintain a rapidrate of growth the air, used to provide oxygen, should be present in theform of fine bubbles under the action of stirring. The air may beintroduced through a sintered surface. Preferably however there is usedthe system of intimate aeration known as vortex aeration.

It has been found that by the use of yeast of the strain Candidalipolytica in a process according to the invention in which aeration iseffected by vortex aeration, a high growth rate is achieved whereby thegeneration time lies in the range 25 hours and the cell concentration isincreased by a factor of up to 12 in two days.

At the end of the growth one obtains an emulsion which contains yeastand nonmetabolised hydrocarbons in a continuous aqueous phase. Thisemulsion is broken down by a first centrifuging in the presence of asurfactant. One obtains:

(a) On the one hand a pasty phase of yeast cells impregnated withhydrocarbons and aqueous medium.

(b) On the other hand an aqueous phase and the greater part of the phaseof hydrocarbons which will be separated subsequently.

The pasty phase of yeasts is subjected to successive alternate washingand centrifuging stages in the presence of a surfactant until theseyeasts are free from hydrocarbons, the last washing being carried outwith pure water. The yeast is then dried under conditions which renderit capable of assimilation.

The hydrocarbon phase and the aqueous phase (to which one adds the wethydrocarbon phases coming from subsequent centrifuging of the yeast) aretreated by decantation or centrifuging to separate the hydrocarbons andthe aqueous medium.

The process may be carried out batchwise. However if desired, any one ormore of the stages herein described may be carried out in continuousmanner.

The treated petroleum fractions will be very suited to a number ofdifferent uses, depending on boiling range and other characteristics.Thus the kerosenes may be employed as aviation jet engine or gas turbineengine fuels; the heavy gas oils are suitable as heavy diesel fuels.Also there may be obtained oils suitable for use as refrigerator oils oras transmission fluids.

The invention is illustrated but not limited by the following examples.

EXAMPLE 1 The feedstock was a heavy gas oil having the followingcharacteristics:

The yeast employed was a strain of Candida lipolytica previouslycultivated on a malt sugar medium and adapted to withdraw its carbonfrom hydrocarbons. This adaptation was carried out by preparing aninoculum by the method now described:

Preparation of the inoculum A culture of Candida lipolytica is made insterile 250 ml. conical flasks. These are open to the air and contain 50ml. of a mineral medium together with 5/10 ml. of the heavy gas oildescribed above. The mineral medium has the following composition:

Monopotassium phosphate7 gm. Magnesium sulphate-0.2 gm. Sodiumchloride-0.1 gm. Ammonium chloride-2.5 gm.

Tap water (trace elements) ml. Difco yeast extract1 ml.

made up to 1000 ml. with distilled water.

This culture is incubated for 3 days at 30 C. with (b) A limpid phase ofaqueous mineral medium. mechanical agitation. (c) A Wet hydrocarbonphase.

ml. of this culture are then taken and added to a The pasty phasecontaining the yeast cells is then washed flask containing the samequantities of the same mineral with water containing 0.25 part per milof the same surmedium and hydrocarbons. The incubation is continuedfactant. Two washings and two centrifugings are sufiicient for 3 dayswith agitation. These same operations are 5 to obtain yeast which isfree from hydrocarbons. Finally repeated 4 or 5 times. the yeast iswashed with pure water at 60 C. to eliminate Two sterile 2 litre toxinflasks, each containing 1 litre the surfactant left in the yeast and itis then centrifuged. of the above mineral medium to which ml. of heavyThe product thus obtained is dried at 80 to 90 C. in

gas oil have been added, are seeded by means of 20 10 a ra id current ofair. mL/Iitre of an inoculum coming from the preceding culture. Thisculture is incubated for 36 hours at 30 C. Recovery of the dewaxed heavygas oil with mechanical agitation. The 2 litres of culture are To theWet hydrocarbon phase from the first centrifugcentrifuged at 30 C. andthe yeasts recovered in the ing, is added the wet hydrocarbon phasesfrom the two centrifuge cups constitute the inoculum necessary forsubsequent centrifugings and the mixture is allowed to one experiment.settle at 30 C., until the water which it contains separates Subsequentstages were carried out by the method now out. (More satisfactorily thisstep is carried out by cendescribed. trifuging.)

The table below gives the numerical results obtained in this experiment:

Initial cellular density-0.800 gm./ litre Final cellular density4.76gm./ litre Growth time11 hours Culture of Candida lipolyrica on heavygas oil There is introduced into a fermenter, equipped with an aerationsystem of a type which forms a vortex in the mixture, 1 litre of thesame mineral nutritive medium as described above (containing 1 ml./litreof yeast extract)' The PH is regulate? to at i beginning 5 Production ofyeast per litre of culture medium and the experiment and is maintainedat this figure during per hour. the culture by the addition ofmonopotassium phosphate.

The air injection is started up at the rate of 50' litres/ 4.760.80 0360 H h hour/litre of the medium and the temperature is main- 11 1 re/our tained at C., and periodically distilled water is added 30 tocompensate for evaporation losses. 0-360 gm/ 6/ hour The fermenter isthen seeded with 800 mg. of the Yield of yeast in relation to the gasinoculum whose preparation is described above, and the gas oil isintroduced in four stages in quantities in an ex- 4.76-0.80 ponentiallyincreasing series, so as to reach in all 25 ml./ 25 0.866 18% by Weighthtre of medlum' Yield of dewaxed gas oil-82% by weight The incubation isstopped when the cellular density (concentration of cells) remainsconstant, that is to say when the stationary phase has been reached. Thecellular EXAMPLE 2 density is measured by taking periodical 25 ml.samples of 40 An inoculum was re and b the method described the culture,the cells of which are filtered, washed until in Example 1. Inplacepofghe feeditock used in Example 1 Pour point dewaxed gas oil- 40C.

the NH ions disa ear and dried. Their content of nitrogen is e stimatedthe Kjeldahl method. Measurements $32 32? employed the gas 011s descnbedm the followcarried out previously on pure dry candida lipolytica gaveThe method of culture and product Separation was as a nitrogen contentof 5 Filom the mtrogen content described in Example 1 except in respectof the scale of of the test sample taken it is possible to deduce thecellular the operation Thus 30 litre fermenters were p y density of theculture at the moment the sample was containing 20 litres of thenutritive medium and in each taken case starting with 40-50 grams ofinoculum.

Recovery of the yeasts Also, in place of monopotassium phosphate, N/ 1ammo- To the emulsion formed there is added 0.25 per mil by niumhydroxide aqueous solution was employed to regu- Weight, reckoned on theaqueous phase, of the cationic late the pH.

TABLE Feedstock Reference A B C D E F G Feedstock Feedafter stockdesulphualter risation Straight run Heavy terroby hydro- Nature ofgas-oil Zarzaltine Irak Kuwait Irak Zarzaitine fining fining Ch t ti fs-oil bet re tr atment, distillation:

i i ti a l li l O 0 e 305 224 198 223 178 305 223 50%, C 327 348 361 366380 327 360 Final B.P., C. 351 390 400 400 400 351 400 Four point, 0....+8 +11 +17 +22 +26 +6 +21 Content of normal paratfins percent by weight3. 3 13. 2 8. 8 14 11. 6 13. 3 12 Characteristics of gas-oil aftertreatment:

Pourpoint, "C "d ...g it.. i azb.. 5 0 16 +3 -25 -9.3

' nta 60111 'mal 3TB. 1113 11 me a OISE Y il rgighti 3 00.3 0.18 0.5 0.87 1. 4 3. 4 0. 1 1, 5 Yield of yeast, based on feedstock (by weight)12. 5 13. 2 8. 1 7. 8 8 16 11. 5

surfactant, ammonium stearyl-trimethyl chloride and the EXAMPLES 3 To 8pH is adjusted to 8 by the addition of caustic soda. The discontinuouscentrifuging of this mixture gives: An inoculum was prepared by themethod described in (a) A pasty phase of yeast cells impregnated withhy- Example 1. The method of culture and product separadrocarbon andaqueous medium. tion was as described in Example 1 except in respect ofthe scale of the operation which was the same as described in Example 2.

The results obtained with different strains of yeast and thecharacteristics of the feedstock used are recorded in the followingtable:

discontinued and the product treated as described in Example 1.torecover separately the yeast and the treated gas oil.

The species of yeast employed and the improvement in cloud point andpour point obtained in the gas oil are Example No.

Origin of gas-oil Hassi Irak Irak Irak Irak Messaoud Kuwait Strain ofyeast used Tomla Candida Toralopsis Hansenala Candida Oidiu'm atilz'stropicalis collicalosa anomala palcherina lactis Characteristics ofgas-oil before treatment, Distillation ata: Initial B.P., C 224 224 223217 235 198 50%, C n 348 348 366 200 294 361 Final B.P C. 390 390 400302 381 400 Pour point, C +11 +11 +22 4 -1 +17 Content of normzfilparaffins, perceint t 13. 2 13. 2 14. 2 9 3. 2 8.8 Characteristics as-oia ter trea men Pour point, 3 -24 -20 15 26 30 20 Content of normalparaflins, percent by we glit. 0.8 0.6 1 O. 0 0. 7 l. 2 Yield of driedyeast, based on feedstock, by weight." 14 13 8. 2 8. 9 8. 2

EXAMPLE 9 The feedstock was a heavy gas oil derived from Irak petroleumhaving the following characteristics:

Density at 15 C./4 C.O.878 Distillation Initial boiling point-220 C.Percent at 250 C.-3 Percent at 360 C.50 Final boiling point405 C. Cloudpoint+21 C. Pour point+l7 C. Paraffins percent by weight-12.8

shown in the following table (initial pour point +17 C.; initial cloudpoint +21 C.):

Particulars of the growth and analysis of the recovered yeast are givenin the following table (initial cell density: 1 gram/litre).

Final Yield, Composition of yeast cells cell percent Mean density, ofgas Free g neration gram/ oil N Lipids, tats,

Genus, specie time, hours litre treated percent percent percent percentCandida, species 8 16 8 9 47 9 4 Candida, Zipolytica 7 13 6. 5 9 47 12 0Candida, pulcherrima-.. 10 5 7. 3 47 7 0. 6 M ycoderma, cancoillota. 716 8 8 48 14 1. 3 Hansen Ma, an0mala 7 16 8 7. 3 45 15. 5 1 Torulopsis,collicalosa 5 16 8 7. 7 4. 1 Oidiam, lactis 12 10 5 7. 3 45 42 2. 5

The aqueous nutrient medium had the following composition:

Grams Diarnmonium phospate 2 Potassium chloride 1.15 Magnesium sulphate,7H O 0.65 Zinc sulphate 0.l7 Manganese sulphate, 1H O 0.045 Ferroussulphate, 7H O 0.068 Tap water 200 Yeast extract 0.025

Distilled water (to make up to 1000 mls.).

A series of seven different yeasts were separately grown batchwise onthis feedstock, the conditions in each case being as follows:

litres of the aqueous nutrient and 75 grams of the gas oil feedstockwere stirred wtih 15 grams of the yeast in a litre fermenter underconditions of vortex aeration with introduction of air at the rate ofvolumes per volume of liquid/hour. Gas oil was added progressively tothe fermenter according to the rate of growth of yeast until a quantityof 3 kilograms was attained, the runs proceeded again until there was nomore significant increase in cellular density-e-then the aeration andagitation were The yeasts as herein described are well suited for themetabolisation of the straight chain hydrocarbon components of petroleumfractions having a mean molecular weight corresponding to at least 10carbon atoms per molecule despite the presence in the fraction ofnonhydrocarbon components such as sulphur compounds and it has not beenfound necessary to remove such components prior to treatment inaccordance with the invention. Nevertheless it will be necessary toensure the absence of extraneous materials used in refining which areinjurious to yeasts, at least up to and including the growth period.Thus it should be noted that furfural must be excluded from thefeedstock, also bacteriostatic agents such as phenols and quaternarynitrogen compounds. Certain metals are also injurious and should be keptfrom contact with the yeast; typical of such metals are copper, lead andmercury.

We claim:

1. A process for the removal, at least in part, of straight-chainparaffinic hydrocarbons from a petroleum fraction having a meanmolecular weight corresponding to at least 10 carbon atoms per moleculeand containing 3-45% by weight of straight-chain parafiinic hydrocarbonssaid fraction further containing naphthenes, aromatics andbranched-chain paraffinic hydrocarbons, and the concurrent production ofan edible yeast, which comprises cultivating a strain of yeast capableof consuming straight-chain paraffinic hydrocarbons and which has beenadapted to grow on straight-chain paraffinic hydrocarbons, in thepresence of said petroleum fraction, an aqueous nutrient medium, and agas containing free oxygen, and after growth of the yeast, separatingfrom the mixture a yeast-containing fraction, an aqueous phase, and apetroleum fraction having a reduced proportion of straightchainparaffinic hydrocarbons as compared with the proportion of saidhydrocarbons present in said fraction initially, and containingsubstantially all of the naphthenes, aromatics and branched-chainparalfins present in said fraction.

2. A process according to claim 1, wherein the pH value of said aqueousnutrient medium has a predetermined value within the range 3 to 6.

3. A process according to claim 1, wherein the pH value of said aqueousnutrient medium is maintained within the range 4 to 5.

4. A process according to claim 1, wherein the pH value of said aqueousnutrient medium is maintained within the range stated by the additionduring the cultivation of the yeast of an alkaline material selectedfrom the class consisting of sodium hydroxide, potassium hydroxide,monopotassium dihydrogen orthophosphate, and ammonia either free or inaqueous solution.

5. A process according to claim 1, wherein said petroleum fractionconsists of a gas oil.

6. A process according to claim 1 wherein said gas oil boils within therange 178 to 405 C. and contains from 8.8 to 18% of straight-chainparaffinic hydrocarbons.

7. A process for the removal, at least in part, of straight-chainparaffinic hydrocarbons from a petroleum fraction, having a meanmolecular weight corresponding to at least 10 carbon atoms per moleculeand containing 3-45% by weight of straight-chain paraffinic hydrocarbonsand said fraction further containing naphthenes, aromatics andbranched-chain paraffinic hydrocarbons, and the concurrent production ofan edible yeast, which comprises cultivating a strain of yeast capableof consuming straight-chain paraffinic hydrocarbons and which has beenadapted to grow on straight-chain parafilnic hydrocarbons, in thepresence of said fraction, an aqueous nutrient medium, and a gascontaining free oxygen, and after growth of the yeast, separating fromthe mixture a yeastcontaining fraction contaminated with hydrocarbons,an aqueous phase, and a petroleum fraction having a reduced proportionof straight-chain parafiinic hydrocarbons as compared with theproportion of said hydrocarbons present in said fraction initially, andcontaining substantially all of the naphthenes, aromatics andbranched-chain paraffins present in said fraction, treating saidyeast-containing fraction for the removal of the hydrocarbons therefrom,and drying the hydrocarbon-free yeast under conditions to yield anedible yeast product.

8. A process according to claim 7, wherein said aqueous nutrient mediumhas a pH value within the range 3 to 6 and wherein said pH value ismaintained within said range by the addition to said medium during thecultivation of the yeast of an alkaline material selected from the classconsisting of sodium hydroxide, potassium hydroxide, monopotassiumdihydrogen orthophosphate, and ammonia either free or in aqueoussolution.

9. A process according to claim 7, wherein said petroleum fractionconsists of a gas oil.

10. A process according to claim 9, wherein said gas oil boils withinthe range 178 to 405 C. and contains from 8.8 to 18% of straight-chainparatfinic hydrocarbons.

References Cited Just, F. et al.: Branntweinwirtschaft 2:113115, 1948.Bruyn, 1.: Koninkl. Ned. Akad. Wetenschap, Proc Ser C, 57: 41-45, 1954.

40 LIONEL M. SHAPIRO, Primary Examiner U.S. Cl. X.R. 19528 mg?" UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,560,341 DatedFebruary 2, 1971 lnvenml-(a) Alfred Champagnat and Jean Antoine FilosaIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3, line 32, "as should read at Column 6, line 30, cancel thisline;

Column 7, line 48, "405C. should read 450C.

Claim 6, line 1, "1" should read 5 Signed and sealed this 16th day ofNovember 1971.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSOHALK Attesting Officer ActingCommissioner of Pete

